Two new main characters are introduced to the Superman mythos in the show: Chloe Sullivan, Clark's sidekick-of-sorts, and Lionel Luthor, Lex's rich and powerful father. Although Lex Luthor's father had previously appeared in the comics, this was the first time his character was fully fleshed out and given the name Lionel.

Season 4 - Introduces Lois Lane for the rest of the series. Clark encounters a new hero Bart Allen also known as Impulse, Clark discover the crystal of knowledge which leads him to the arctic after stoping a second meteor shower.

Season 8 - Lana and Lex have left, and it takes place more in Metropolis now. Clark works at The Daily Planet alongside Lois, The news becomes aware of an anonymous hero known only as the Red-Blue Blur saving people while a threat of a serial killer known as Doomsday is also at large plaguing the city.

Season 9 - Introduces a younger Zod, a clone from his time as a Major. The S-Shield featured more prominently in this season including on Clark's chest. Clark adopts a black outfit, calling himself simply The Blur.

Season 10 - The final season of Smallville. This season features the return of Lex Luthor, as well as the appearance of Darkseid. Chloe Sullivan is no longer a regular in this season, appearing only as a recurring guest star. And the real Superman costume finally appears.

Other Media

Prose

Upon Smallville's launch, a series of paperback novels was launched, along with a series of young adult novels. These stories chronicled some of Clark's adventures that took place during the first few seasons. Both series died out before too long. See Smallville novels for information on both series.

Comic Books

Addtionally, there have been comic book adaptations of Smallville. During the first few seasons, a comic series simply titled 'Smallville' ran stories taking place concurrently with the show. It also had special features, like episode guides and interviews with the actors.

Additionally, one online comic story was made in conjunction with Stride Gum, entitled Smallville: Visions.

After the show's final season ended, Smallville Season 11, a new regular comic series, continued the story from the TV series.

Webisodes

Chloe Sullivan had her own live-action series of webisodes, called the Chloe Chronicles, which tied in with current episodes of Smallville. The series was later renamed the Vengeance Chronicles.